This invention relates to high voltage circuit breakers, and more specifically relates to a novel dead tank housing structure for high voltage circuit breakers which employ at least three puffer-type interrupter assemblies which are disposed parallel to one another and to the axis of the tank and are supported in cantilever from one end of the tank.
Puffer type circuit breakers are well known and are frequently contained within a dead tank type of housing structure.
Circuit breakers of the general type to which the invention is directed are well known. By way of example, a conventional circuit breaker employing puffer type interrupters contained within a dead tank housing for a 145 kV, 40 kA circuit breaker is shown in the product catalog of Brown Boveri Corporation, CH-A-061 312E. Circuit breakers of this kind are also described in the Brown Boveri Review dated April 1978, Volume 65.
The novel dead tank housing structure of the present invention eliminates numerous expensive components and permits simplified assembly and maintenance of circuit interrupters which are contained within the tank. Novel features present in the new dead tank arrangement include:
(a) The bushing structure which is associated with the dead tank contains a novel integral rod and plate configuration which substantially reduces the cost of the bushing and simplifies its maintenance and assembly.
(b) A novel corona discharge prevention ring is formed of a flexible metal tube which is slotted along its length and then forced over and along the periphery of openings in the tank through which the bushing conductor extends. This novel tube serves as an inexpensive corona ring around the sharp corners of the openings which receive the bushings. Since it is a flexible member which is readily commercially available, it can easily follow the shape of any surface on which it is fitted.
(c) A novel filter drier structure, which employs a flat, elongated body, is located in a region of low electric field stress along the bottom of the horizontal cylindrical tank which defines the main body of the dead tank container. The filter mounting permits ease of maintenance and the parts which are required to form the assembly are inexpensive.